Steel and aluminum lids for beverage and food cans are called "ends" in the can industry. Two piece cans comprise a can body member and an end member which is fixedly attached to the can body member by a seamer machine after the can body member has been filled by a filler machine. Due to the cross-sectional shape of the ends, they nest together when stacked or conveyed and form a continuous string, referred to as a snake. In order to transport and store ends, segments or stacks of this string (sometimes referred to as "sticks") containing a known count of ends (around 500) are divided from the string manually by an individual called a "bagger" and inserted into a paper tube called a sleeve. The sleeves are then sealed and the bagger stacks the sleeves on a pallet in a nested fashion. The nested sleeves of ends are maintained in relationship on the pallets by threading a paper or net ribbon back and forth around the layers. The pallet loads are hand assembled at the end manufacturing facility for shipment to the user (bottler-filler) facility. The beverage filler operator at the bottling plant opens the sleeves and feeds the stack of ends to the seamer machine.
This delivery system has been the industry standard for many years. During this time end manufacturing lines have become highly automated and greatly improved in speed. There have been a number of attempts at improving the delivery system but most have only improved the ability of the bagger and filler operators to keep up with the system and have not truly automated the system.
Recently, there has been a machine developed called a "balancer". This machine has the ability to take segments of the string of ends being conveyed and transfer the segments into a multi-rowed steel tray or simply transfer from an incoming conveyor(s) to an outgoing conveyor(s). The device makes decisions based on line conditions to either off load ends to the tray, send ends on through the line, or load ends from the tray back into the line. In other words, the machine acts as a device to balance the flow of ends through the manufacturing line; hence, the name "balancer". A machine of the type is disclosed in U.S. Pat. No. 4,808,057.
The developer of the balancer has also developed a machine that places ends in plastic trays and then palletizes the trays for delivery to the filler-seamer line. The machine with modifications is also used as a depalletizer to unload the trays at the filler. A machine of this type is disclosed in U.S. Pat. No. 4,568,231.